Stem cell therapy for heart failure: two studies two successes

By Dr. Ananya Mandal, MDNov 17 2011

The Center for Disease Control and Prevention says that heart failure affects nearly 6 million Americans leading to considerable risk of death, diminished quality of like and recurrent hospitalizations. Heart failure occurs when the heart can no longer pump enough blood to the rest of the body. The most common cause of heart failure is coronary artery disease, which narrows the small blood vessels that supply blood and oxygen to the heart.

Stem cell therapy from another person

Promising results of a Phase II study on heart failure were presented Monday at an American Heart Association meeting in Orlando, Florida. The study, sponsored by Mesoblast Ltd. (MSB), found that patients with heart failure can now reduce future occurrences by as much as 80 percent using an experimental stem-cell treatment called Revascor, which is Mesoblast’s experimental drug. Revascor is derived from mesenchymal stem cells from another person.

The researchers included patients between the ages of 20 and 80 who were tracked for at least 12 months. In the study, 45 patients who have had previous history of moderate to severe congestive heart failure were give an shot of Revascor along with standard medicines. The negative control group had 15 people and didn’t receive the treatment.

Results showed that the therapy was safe and well-tolerated at all doses an overall risk of a major adverse cardiac event was cut by 78 percent. During the follow-up period of 22 months, one patient in the group receiving the Revascor treatment died, while three fatalities were recorded in the control group.

Researchers explain that mesenchymal stem cells have the ability to differentiate into any other cell depending on the cellular signals it receives. The underlying theory is that the stem cells will differentiate into cardiac cells and will repair the damaged areas affected by heart failure, thus improving the damaged heart’s ability to pump out blood.

Mesoblast representatives said that it expects to enter Phase III trials in the first half of next year. The treatment is projected to go on sale by 2015.

Stem cell therapy from one’s own body

In yet another study stem cells harvested from a patient's own heart were used successfully in repairing a failing heart. This study was based on the results from a trial presented this month at an event held by the American Heart Association.

The clinical trial, dubbed SCIPIO (Cardiac Stem Cell Infusion in Patients with Ischemic cardiOmyopathy), is in early-stage testing and is being conducted by Roberto Bolli of the University of Louisville and colleagues.

This was a Phase I study involving 23 patients with weak hearts. These patients had an ejection fraction of less than or equal to 40 percent before coronary artery bypass grafting, or CABG. Ejection fraction is a common measure of the heart's efficiency. Healthy hearts usually have results between 50 percent and 70 percent.

Out of the 23 patients, 16 were assigned to the treatment group and were administered their own cardiac stem cells infused via a balloon catheter nearly three to five months after CABG. The control group had seven patients and they received standard care.

Results at four months after receiving the cardiac stem cells infusion showed that the patients' ejection fraction increased to 38.5 percent from 30.3 percent. By contrast, there was no change in the ejection fraction of patients during the same time frame in the control group. Cardiac stem cells infusion, or CSC infusion, had a more pronounced effect on the efficiency of heart at year 1 with eight patients in the treatment group exhibiting an improved ejection fraction of 42 percent. MRI scans of patients in the trial also demonstrated that the new treatment reduced scarring in the patients' hearts.

SCIPIO is the first study to use a homogeneous and pure population of cardiac stem cells in humans, according to Bolli. Though cardiac stem cells infusion is still at an early stage of development and further clinical trials are required, researchers hail the findings of the trial as a potentially major breakthrough.